1. Field of the Invention
This invention relates to methods for determining the altitude of an aircraft. More particularly, this invention pertains to such a method for use in an aircraft that is equipped with a radar altimeter and an additional non-radiating flight altitude measuring device.
2. Description of the Prior Art
A radar altimeter is often used to determine the altitude above ground of an aircraft (including fixed-wing and rotor aircraft and missiles). A disadvantage of the use of such device is the emission of high-frequency power whose reception may enable detection and location of the aircraft. Detection range increases with altitude above ground, angular position and emitted power. Since, on modern radar altimeters, for example, power is controlled as a function of the signal-to-noise ratio of the received signal, that emitted power increases with altitude.